Class: YamlDb::SerializationHelper::Dump

Inherits:
Object
  • Object
show all
Defined in:
lib/yaml_db/serialization_helper.rb

Direct Known Subclasses

CsvDb::Dump

Class Method Summary collapse

Class Method Details

.after_table(io, table) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 163

def self.after_table(io, table)

end

.before_table(io, table) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 151

def self.before_table(io, table)

end

.dump(io) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 155

def self.dump(io)
  tables.each do |table|
    before_table(io, table)
    dump_table(io, table)
    after_table(io, table)
  end
end

.dump_table(io, table) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 171

def self.dump_table(io, table)
  return if table_record_count(table).zero?

  dump_table_columns(io, table)
  dump_table_records(io, table)
end

.each_table_page(table, records_per_page = 1000) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 183

def self.each_table_page(table, records_per_page=1000)
  total_count = table_record_count(table)
  pages = (total_count.to_f / records_per_page).ceil - 1
  keys = sort_keys(table)
  boolean_columns = Utils.boolean_columns(table)
  quoted_table_name = Utils.quote_table(table)

  (0..pages).to_a.each do |page|
    query = Arel::Table.new(table).order(*keys).skip(records_per_page*page).take(records_per_page).project(Arel.sql('*'))
    records = ActiveRecord::Base.connection.select_all(query.to_sql)
    records = Utils.convert_booleans(records, boolean_columns)
    yield records
  end
end

.sort_keys(table) ⇒ Object

Return the first column as sort key unless the table looks like a standard has_and_belongs_to_many join table, in which case add the second “ID column”



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# File 'lib/yaml_db/serialization_helper.rb', line 204

def self.sort_keys(table)
  first_column, second_column = table_column_names(table)

  if [first_column, second_column].all? { |name| name =~ /_id$/ }
    [Utils.quote_column(first_column), Utils.quote_column(second_column)]
  else
    [Utils.quote_column(first_column)]
  end
end

.table_column_names(table) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 178

def self.table_column_names(table)
  ActiveRecord::Base.connection.columns(table).map { |c| c.name }
end

.table_record_count(table) ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 198

def self.table_record_count(table)
  ActiveRecord::Base.connection.select_one("SELECT COUNT(*) FROM #{Utils.quote_table(table)}").values.first.to_i
end

.tables ⇒ Object 



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# File 'lib/yaml_db/serialization_helper.rb', line 167

def self.tables
  ActiveRecord::Base.connection.tables.reject { |table| ['schema_info', 'schema_migrations'].include?(table) }.sort
end